1. Field of the Invention
This invention relates to apparatus for non-destructive testing of internal combustion engine cylinder heads for detection of leak-causing cracks.
In testing cylinder heads for cracks, a variety of conventional non-destructive testing methods may be used, such as ultrasonic testing, X-ray testing, dye penetrants, etc. However, since cylinder heads are roughly cast, apart from machined surfaces, many surface cracks and other defects are present which severely limit the effectiveness and usefulness of such methods. Surface cracks and many other defects are of little or no interest to the engine rebuilder, since it is in most cases only those cracks which produce leaks, resulting in loss of engine compression and/or loss of engine coolant, which are of concern.
Leak detection is thus the primary concern, and generally speaking the only effective means of detecting leaks is to seal the water passage ports in the cylinder head, connect the head to a pressure source through a water passage port, and then monitor for leaks. The present invention relates essentially to apparatus for facilitating leak detection through such pressure testing.
Pressure testing is desireable not only at the stage when the rebuilder is considering whether or not to recondition a cylinder head, and is trying to determine the existence and location of any leaks, but also after crack repairs have been effected, to verify the integrity of the repair.
2. Description of the Prior Art
Cylinder head pressure testing apparatus is known in the prior art. For example, R. R. McGlogan Equipment Ltd. of Ariss, Ontario, Canada has for some time manufactured and sold head pressure testers comprising a cylinder head mounting frame, hold-down arms attachable to the frame and positionable with respect to the cylinder head, and screw-down plugs attached to the hold-down arms for screwing into contact with the cylinder head to seal the water passage ports in the head. An air pressure source is then connected to the head, and using a soap solution or other means, the cylinder head is examined for leak detection. While this apparatus performs very well and has achieved good market success, it was desired to improve the state of the art by by providing apparatus which ideally would both simplify and improve the testing.